(CNN) -- A man seeking about $660 in unpaid wages walked into an office building in the northwestern Chinese city of Urumqi on Thursday and detonated a bomb, killing himself and injuring two employees, the state-run Xinhua news agency reported.

Before the bomb exploded, Han threatened office workers and demanded that he be paid 4,500 yuan (U.S. $662), the news agency said. Police said Han had sued the company for the money, but lost the case in July.

"Han walked into the first floor of the building, and talked to an office worker, saying, 'Society is unfair. I don't want to live any more,'" police said, according to Xinhua. He wanted to talk with the head of the company.

The office workers who were injured were trapped in a room with Han, and tried to reason with him, police said. A third worker escaped.